Having a different sex drive than your partner can be a tough obstacle to overcome. Of course, there is no magic number of times you should be having sex, but if you feel like you're just not enjoying sex like you used to or don't want to have sex as often than you used to, you might be suffering from a low sex drive.

While you won't know for sure what the culprit is until you talk with a doctor, these common reasons for low libido may point you in the right direction.

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You're really tired.

Being too tired to have sex is an old cliche, but it turns out there may be more to it than we once thought. A study by the National Sleep Foundation found that one in four married Americans say they are often too tired at the end of the day to have sex with their partner.

You're depressed.

When your mental health is not in order, you may not want to do much of anything, let alone have sex. If you've been experiencing symptoms of depression or any other mental illness, this can be taking a toll on your desire to have sex, Dr. Constantine George told INSIDER.

Additionally, if you are currently on anti-depressants, that can also affect your sex drive. But that doesn't mean you should stop treating your symptoms to get your libido back: You can talk to your doctor if you're concerned the medicine is the culprit and try to find a prescription that's better for you.

You're not hitting the gym (or the yoga mat or the trail).

Getting the blood pumping in your workouts can help you get the blood pumping in the bedroom. A lack of exercise can greatly decrease your desire to have sex, Dr. William Kolbe, author of "The Rejuvenating Power of Masturbation," told INSIDER because it can affect your hormones.

"Being physically inactive, putting on extra weight, mental stress can all cause changes in our hormone production, especially the sex hormones testosterone and estrogen," he said. "Testosterone has many functions, among them is maintaining sexual desire, our libido. When our sex hormone production is diminished or out of balance, then generally it becomes more difficult to find the initiative for sex."

You're not eating well.

We all love a good piece (or three) of pizza, but if you're not giving yourself a balanced diet, your sex drive may be suffering a big blow.

Fried and salty foods can make you bloated, and if you've ever eaten a plate of french fries, you'll know that sex is often the last thing you want.

Studies have also shown that a balanced diet can increase your sex drive along with certain foods, so if you need a little boost, put down the corn dog and pick up the watermelon (who knew?).

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You're not feeling yourself.

How can you expect anyone to dig you if you don't dig you?
Unsplash/Kyle Broad

If you're not feeling good about yourself, you're probably not going to want to have sex with someone else. Your self-image might actually be plaguing your chances at a happy sex life.

"People harboring attitudes of low self-esteem, low self-worth, or lacking in self-love can easily lose interest in sex," Kolbe said. "The mind is our foremost erogenous zone and if it is mired in negative or limiting self appraisals, feelings of not being worthy, then consequently people will regrettably choose to forgo activities such as sex that are stimulating and satisfying."

If you feel yourself thinking negative thoughts about yourself and your body, talk to your partner about how you can make yourself more comfortable during sex. Find a way to make yourself feel sexy again and, if need be, talk to a therapist about how to regain confidence.

You haven't been getting anything out of sex.

If you're not getting your needs met by your partner, there's really not going to be much motivation for you to want to have sex at all.

Think about what you'd like your partner to do that would make you more excited at the prospect of sex and ask them if they'd be comfortable doing it. Your partner should be open to finding some way to make sex good for you too, so talk it out.